Comment 1 for bug 1832160

juju offer doesn't use -m because the model to use is part of the offer URL. This allows the offer command to work correctly across different controllers. The offer command is a so called "controller" command and not a "model" command. Many juju commands like "add-model" etc also operate as controller commands, where -m is not required.

eg
juju offer mymodel.myapp:db
juju offer myctrl:mymodel.myapp:db

Without the controller/model part of the URL, juju offer does default to the current model as would be expected.

The same logic then also applies to show/find/remove offer.
ie you show an offer based on its URL. The URL may leave out the controller and model parts, in which case it defaults to the current controller / model.

Hopefully this clarifies the usage.